People suffering from poor visual acuity many times find relief by using vision correcting lenses, i.e., ophthalmic lenses. These may come in the form of corrective lenses fitted into eyeglasses. For their manufacturing, the desired optical characteristics of the ophthalmic lenses (e.g., sphere power, cylinder and cylinder axis) are determined in the following way: the patient is given a visual acuity test (i.e., eye vision measurement procedure)—be it objective (using an auto-refractometer for example), or subjective (using a trial frame or a phoropter fitted with trial lenses). The outcome of the test is a prescription (i.e., original prescription) according to which the ophthalmic lenses for correcting the patient's vision can be manufactured.
When considering patients suffering from myopia or presbyopia, the patient goes through an eye vision measurement procedure for determining his prescription for far vision and/or near vision correction. In this procedure the patient is usually instructed to read a hand held book (in near vision measurement) or to look at a testing board with symbols (in far vision measurement) using different correctional lenses. The optimal correction lenses for far vision and/or near vision are then selected, and the far vision and/or near vision prescription is prescribed to the patient by the prescriber.
The existing different eye vision measurements are performed according to various procedural protocols and under different conditions. These procedures are characterized by a plurality of parameters which influence on each eye vision measurement, and usually are not taken into consideration when a prescription is provided to the patient. These parameters can be geometrical and optical parameters that can be expressed by means of distances, angles, and optical characterizing parameters. Instead of taking into consideration the different values of these parameters, usually default values are used. This lack of uniformity between the parameters, and the use of default values for these parameters, usually results in inaccuracy in the prescription that is provided to the patient.